A flickering check engine light with a rough idle is usually a misfire warning, not a cosmetic glitch.
On a Fiat Panda III, ignition, intake and fuel faults are the first things to inspect.
What a flickering light and rough idle are telling you
On your Fiat Panda III, a check engine light that flickers intermittently while the idle feels lumpy is usually the ECU reporting a live misfire. The flashing is deliberate: it warns that unburnt fuel is reaching the catalytic converter, which can overheat and fail. It is not the same as a steady light. Even if it comes and goes, treat it as a prompt to diagnose the car soon, especially if the idle shakes, the exhaust smells rich, or you feel a hesitation under acceleration.
